Seth Meyers holed up with a group of writers at Gurney’s Inn in Montauk late last week to work up material for his gig as host of the ESPY Awards next month. Meyers’ informal writers retreat lasted two days, spies said. The only time he and his crew emerged from their marathon joke-writing sessions was to hit the Port of Call Bar for beers and banter. The pressure’s on for the “SNL” writer after he got high marks for emceeing the White House Correspondents Dinner — and glares from Donald Trump — and the Robin Hood Foundation gala.